a lot of review of policies and certainly where paul ryan stands on the issues, where romney stands on the issue, but this camp was all about kind of gearing towards a mock debate. he did one each night the last four nights bringing him a a total of at least half a dozen he's done. 90-minute mock debates very much like we'll see tonight, ashleigh. >> called a gaffe machine, among other things. what has he been doing, or at least what has the campaign been doing or allowing us to know about, anyway, to try to minimize the gaffes that could lead to what john king referred to, internet moments that live forever? >> reporter: that's right. when you think of joe biden, he's almost synonymous with gaffes. things we see when he's on the campaign trail. certainly his words sort of trip him up and become these moments. the thing is, and i've asked his folks about this. they sort of say they're not really worried about it. i think certainly when you're dealing with joe biden there's always kind of that in the back of your head, but actually, if you look at his debate performances and he's had ma